CA2039920A1 - Method of preheating a heavy oil zone through existing bottom water and then diverting steam into the oil zone - Google Patents

Abstract

F-5726;

METHOD OF PREHEATING A HEAVY OIL ZONE
THROUGH EXISTING BOTTOM WATER AND THEM
DIVERTING STEAM INTO THE OIL ZONE
ABSTRACT
A method for recovering viscous oil from a formation having a bottom water zone below an oil containing zone. Steam is directed into the bottom water zone thereby heating this zone and an oil containing zone thereabove. Afterwards, steam injection is ceased and a gellable composition is directed into the bottom water zone where it forms a solid gel. Once the solid gel has formed, steam is injected into the bottom water zone where the solid gel causes it to flow upwardly into the oil containing zone. Oil, water, and steam are removed via a recompleted producer well.

Description

F-~7as -1-q'HQI:~ OF PRE~EATI~TZ A I~EAVY OIL ZON~:
THROUGR EXISTING BOTTC)~ TER A~
I)IVERTI~IG ~AM ~NTO q!HE OI~_Z~

This ~pplioation is relat~d to copenCllng appllcation Serial No. 068,290 ~iled July l, ls~7. I~
., i~ Rl~o ralated to Serial No . 292, 7~ which W2~ filed on ;l ~nua~y 3, ls~8s . It is further relat~d to Seri al S No. 292, 799 whlch wa~ ~iled on J'anuary 3, l~a9 .
~his invention rel~t~s ~o the heating of a relatively impermeable formation through ~team heating of a bot~om water zorle and then divert1ng this ~team into c~verlying oil zc:nel; through the ac~ion of a Colid g~l in the bottom water zone.
In ~he recovery Or o~l Srom oil-containing ~ornlation~ is usu~l ly possibl~ tc~ reooYer only minor por'clon~ of ~he origirJ~l oil-in-place by ~o-called primary rec~o~rery methods which utilize only natural force~: . To increase the recovery of o~ l A
variety o~ 5upplement~ry recovery tec:hnique~ are e~p~ yed~ ~hesx techniques include waterflooding, ml~ci~le ~looding, ~he~mal recov0~y, ~nd ste~m flood~ ng.
A problem tbat ari~e~ in variou~ flooding pxoc~a~e~ i~ th~t dl~eren~ E;trata or ~ones ln the reservo~r o~t~3n ~osse~s differ~nt permeabilities~
~hue, displaaing fluid~ enter high permeabillty or "thie~" ~one~ ln pre~renc~a t~ zones of lowe~
pexmea~ility. signi~icant ~uantitles of oil may be l~ft in zone~ o~ lowe~ pcnneability. T~ ¢ircnmvent thi~ ~di~ficull:y th~ technique o~ pror'ile ::antrol l~
applie~ to plug the high permeability zone~ wi~h polymerio glalG and thu~ div~r'c ~che dl~placing ~luid into the low permeab~llty, ~ll rich zone~. Among the pol~mers ~xamined ~r improving waterflood confor~nance ar~ m~ l cro~-link~d polysac- charid~ etal ~0 d ~OO N Zl: 1 I~' S ~ 8-0~ :131 ~dO lIO ll~O~i oross-linked polya~ryl~ s, and organic ~ross-linke~
polyaarylamide~, Another proble~ tha~ arise6 when ~team flooding a ~ormation having a non-aquifer bot~o~ water zone 1~
th~t on o~ca~ion ~te2m channel3 into khe ~ottom w~ter zone~ Th~s botto~ water ~one has rela~iv~ly high per~eabllity wnl~h allow~ high St¢~m and wate~ mobili~y therethrou~h. It ~ difficult to re-dlrect the steam lnto upper por~ion~ of ~he reservoi~ or formation since 1~ ~tc~m prefers th~ path oÆ lea~t resistance. The path of least resistance ln t~ ituation happen~ to be the bottom w~ter zone.
Therefore, wh~t i~ needed i~ ~ method ~or prevonting ~te~m chann~llin~ in a bottom water zone wh~c~ will allow steam to bo r~direCt~d into ~n upper ~on~ o~ ~ re~ervol~ 50 tha~ hydroaarbon~ceous ~luids can be removed therefrom.
~hl~ invention i~ directed to a method for ha~ting a form~t~on throu~h a non-aqui e~ botto~ wat~r z~ne and th~ ~ubsequen~ diversion o~ ~t~am into a preh~at~d formation viscou~ oil ~ontaining zon~.
Ste~m ls first injeo~:ed ln~o tha bottom water 2c>ne. W~tll comm~ln~cation ia e~tabli6hed with a p~ducer or p~od~er~. The bottor~ water zone lg used 2s in 1 leu c~f injeatlns1 into the v;scous oil zone direotly dUR to anticipated lnjec:tivity problems. Injec~ion of steam at low ~uality i~ contlnued for a tim~ suf~ic~ent to preheat ~ome o~ the l~wer and mlddle par'c~ of the oil zone~ When the tempe~atu~a o~ the ove~lylng oi~
30 zone rQaches a de~ir~d t~mper~tu~e range, steam in~ecti~n is t~mporar~ly ~e~m$nat~
8inc~.Gommunic~tion ha~ occurred betwoen the injec:tox and produ~er well~ in the bottom w~ter zone, di~icult to no~ redirQct steam intc~ the oil zone 35 to give th~ needed conv~c~ heating for oil product~on. ~hi~ problem iEs eolved by in~ecting a gQllabl~ compQ~i'cion cap~ble Or in-~1tl~ polynlerization ~O d ~OO N Zl:T 16'S ~d~ at~8-0~ :131 ~dO lIO lIaOW

3 ;.~ ~i 2 ~3 to ~orm polymer gel ~ into ~he bot'com water zone at th2 producing well ~ Polymer gel~ ~re of ~ type thA'c can wath~tand hlgh temper~t~res. PenetXat$on of th~
composltton into the bottom waker zone ~houl~ be 1/3 to 1,J2 the dis~ ce to th~ lnjector, depending upvn pro~ected econemic~:. The pr~du~er well i~ recompleted abov~ the bottom water zone. Care must be taken not to complete th~ produaer too ~lgh above the w~srmed oil 20n~ . Steam ln~ ~ction l"to the bottom water i~ now r~sumed, However, the bottom water zone 16 now block~d ofP. With t~ bloclcage o~ the bottom wat~r zone, steam is ~ire~ted tlp~ardly into the warmed oil zone and oil is produced fro~ ~he same ~one at the producer~
Gravity aids thi~ p~oces: sinc:e steam ~IB redi~c'ced upwardly.
It i~ ~her~3~ore an ob~ e~t of thi~ invent i on ~:o p~ovide for ~ gellable composition which aan be delivered 1 nto a heated bottom wats~ zone h~ving el t~mperatur~ su~ficient to a~ivate said composition and ~er}n a solid gel ther~ln.
~t ~ another ob~ect o~ thi~ in~ntion to p2ovi~l~
~or a composi~ion that will minimize g~31 dam~ge to ~n ~pper productive zone whil~ clo~ing pore3 in a haated higher permeability bvtto~n water zone.
~IG. 1 is a diagrammatic plane view o~ a ~ormation where S'C~a~ iE~ pa~6ing through a b~ttom water 70ne in'co a produation w~ll.
FI~;. 2 i~ a diagranunatic plan~ vlew where th~
lowe~ bottom wa~er ~one ha~ b6~en parti~lly close~ ~ith a g~llable compc3ition ~rhile ste~m 18 pas~ing through an l~pper hydroc:arbonaceous flUid bear1n51 zone or area.
In the prActl~ o~ thls lnventiolJ, xe~errlng to Fig. l~ ste~m i~ ctad by ~t~am ln~ector 8 lnto in~eator w~ll lO. S~Qam exits injector W~ll lO via perforations 2~ So as to c:reat~ a ~;team Zon~ 24 in bot~om Watsr Zone 18. Steam aontinue~ i:'lowing~ through bottom water zone ~8 ~here the perm~bility i3 ~O'd ~00'N Zl:T T6~S 3d~ 9~8-0J :131 ~dO lIO lIaOW

.
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lF--5726 ~4~ ~ ?s su~tantiall~ greater th~n vl~cou~ oil bearing zone~ 14 an~ l6. Becausa ho~tom Wat~r zohe 18 ha~ A
p~rm~a~ility ~ubst~ntially yre~t~r than th~
perm~ability of ei~he~ zon~ 14 or 16, Zohe lB ~ecomsfi a relat~vely hi~h s~am ~nd water mobllity zone~ Visco~s oil contai~ed ln zonea 14 and 16 oan compri~ tar ~and~. Ste~m i5 cohtinually ln~ected into ~team zo~
24 and exi~ that zone ~ia per~or~tions 22 in~o produ~er well 121 Stea~ i~ in~ected into bottom wate~ zone l~ ~o~ a time sufflcient ~o hea~ zone 18 to ~ temperat~re in ~xees~ of about 2~0-F. In~ectio~ or steam into ~ottom wa~er zone 18 ~lso ~ause~ a~ incr~ase ln the temper~ture of upper ~ormatIonY 14 and 16. Steam lS in~ction ~n~o bot~o~ water zone 18 lfi con~inu~d until vi~co~s oil cont~ln~d in zones 14 and 16 ~ecome~
mobile. The tempera~ur~ obtained in 20ne8 14 and 16 or botto~ wa~e~ zone 18 will of course dapend upon 'he ~team in~ection ra~e, temper~ure~ and pre~sUre of the ~te~ being injected lnto in~e~tor w~ 0. The longQr ~ea~ i~ in~ec~d lnto tne ~o~mation, the hotte~ the temperature in zone~ 1~, 16 and 18.
After obtainlng the d~si~ed temp~ratUr~ in zone3 14 and 16 BU~i~iCient to mobil ~z~ viscou~ oiI cont~ined 25 thereln, s~eam injection into injector w~ll lO i~
aeased. Subse~ ntly, ~ gellal~le compositiotl is prepare~ abo~e ground ~or injection into ~leated bottom water zon~ 18. Th~ gellable composition i Iorrnulated So a~ to ~llow penet~atihn into th~ bottom water zone 30 for ~ di:tan~e ~ about lJ3 to 1/2 t~e distan~e from the in~ ac~or well . Initiator~ and r-atarder~ or inhibi~oro ~an be incllld~d ln~o ~he compos ~ tion to obtain ~h~ desired penetration. since pen3tration must be cc~ntrolled, thi~ ~e~hod iæ intended ~r us~ in a 35 non-a~uif~r bottom water zonQ.
While bot:tom wat~r ~one 18 i~ o~ a te~nperaturo gr~a~er th~n about ~10~, a g~ bl~ composition is ~Q-d ~00 N Z1:1~ 16'5 Id~ 9~8-0~ :131 ~0 lI0 lI~UW

y~
F-572 6 _5 _ in~ected into bottom water Zone 18. Th6~ ~el is allowed to remain in 20nQ lB ~or h tlm~ u~ficie~l~ to ~orm a solid gel ~8 ao ~ B ~hown in ~ig. 2 . Th~ solid g~l that form~ l~ capable of wlth~tandlng ~empera~c~re~ grea~r th~n about 210~.
Onae ~olid gel 28 ha~ formQd steam ~nject~on i~
again commenced int~ 'che formatlon by in~ tor well lO
as beforq~. ~s is l3hown ln Fig. 2, ~;'ceam exiting in~ector well lO ~ia per~oratlon~ 22 en~ountar~ ~olld l ~el 2~ And continues to heat oil con~cained in zone 16.
In or~er to re~ove vlscou~ oll from zone 16, produ~e~r ~ell ~.2 i~ recompletes~ ~u~Ficiently above zone 1~ via additional perfora~lonsl 22 50 a~ to allow 1uid commun ~ ~ation with zon~ 16 . Steam inj eoted into zone 16 ~vi~ inject~r well lo ~leat; up oiî ~n zone 16 and cause~ it to flow into producar woll 12. Steam injeC~i~rl lntD ~o~e 1~ continue~ until ~ufficient oil ha~ been remo~r~d ~rom that zc~ne by produc~ well 12 Yla pump 6.
There ar~ ~everal g~lla~le composition~ which can ~e usad to form ~ ~olid ge~ in zon~ 18. Th~Ss lnclude, but are not limited to, an ln~ u gellable com~osltion di~closed in U. s . Patent 3, 557, 562 w~lich contalns ~crylamide mono~ner, methylene bls-acrylamid~ a~ an organlc cro~ l inker, and a free ~adiaal inltlator.
Thi~ p~tent ~s incoxpor~ted l~y referen~e herein. This ~stem undergoes polyDerization in the ~orm~tion to give a polyacrylamide cross-linked wit~
m~hyl~ne-~is-ac~ylamid~. However, ~h~ co~i~y o~
~he ~ollltion ~hen ln~ected is llke that of water~
MechAnic~} 1 sala~lon is r~3~auired ein~e the~e solu~ion~
are ~uite capabl~ of penetratinq low permeflb~ y~ oil bearing ~one6.
A p~ ymeric gel lable compo%ition i~ di~lo~d in U. S~ Patent N~ ~, 658, ~98 wl~iah i~u~d ~o Paul Ana Strom o~ April ~l, 1987. ~rhi~ patent disaloses an agueous ~olution o~ hel~ropoly~charide S-130 combined 01 ' d POO N Zl: T 16' S Id~ 9~-0~ :131 ~dO lIO lIEOW

F-5726 -~- 2 ~ ~3 {~

with lnorganlc c~tions which rorm3 gels ~t elevated t~mperature~. U.S. P~en~ No. 4,716,g66, i~su~d to ~hu on January 5, 1~8~, dlaclose~ A g~l ~ormed by ~mino resins ~uch a~ mela~nins~ ~ormaldehyd~ wh1ch modi~y 5 biopoly~n~r~ in combi3~ation with tran~itional met~l ion~. ~he~e patent~ are hereby incorparatçd by ~ J
referenc~ herein.
Another ~ellable oompo~itlon which c~n be used herel~ is dis~losed in U.S. Paten~ ~o. 4,834,180 ~hich lssu~d to Shu. Thi~ pat~nt discl~ses a cros~-linkable polymer whioh include~ xanthan blopolymer~, h~e~opolysaccharld~ S-130, poly(acrylamid~-co-acrylam~do-2-methylpropanesulfonate )l a~d acryl~mide ~odi~ied pGlyvlnyl alcohol. ThR
l; cross linke~ i~ a par~ y methy~ated aminoplast r~sin whioh cro~-link~ with the polymer therehy formlng a yel in the Absence of a s~l~ whi ch 1~ acid generatin~
upon the applicatlon of heat. ~hi~ paten~ is hereby lncorporatQd by re~erence herein.
~team~lo~d proce~se~ which can be ut;lized wh~n em~loying the~e gels de~crik~d above are detailed in U.S. Patent Nos. 4,4~,783 and 3,918,521 l~ued to Shu and Snav~ly, re~pe~tivel.y. These patents are hereby X
incorporated by re~erence herein.
Although the present inventio~ ha~ h~en descrlbed with preferred ~m~odimont~, it 1~ to b~ under~tood that modi~lcations and va~iations may ~e res~rted to without ~epArting from th~ spirit and scope o~ this invention, as thos~ sXilled in ~he art will readlly understand.
Such modifiaations and v~1ation~ ~re consi~ered to he wi~hln the purvie~ and scope of the appen~ed claims.

Il`d ~30'N ~1:1 16'5 ~d~ 8-0~ :131 ~dO liO ll~nw

Claims (6)

1. A method for recovering viscous oil from a formation having a bottom water zone therebelow comprising:
a) injecting steam into said bottom water zone via fluidly communicating injector and producer wells for a time sufficient to heat oil in a zone above said water zone to a temperature sufficient to mobilize said oil, b) thereafter injecting into said formation a gellable composition in an amount sufficient to form an in-situ solid get in said bottom water zone;
c) allowing said composition to remain in said bottom water zone for a time sufficient to form a solid get thereby blocking said water zone to steam flow therethrough;
d) recompleting the producer well so as to cause fluid communication with a heated oil containing zone; and e) injecting steam into the injection well which steam flows upwardly over said solid gel and removes oil from said heated zone via said producer well.

2. The method as recited in claim 1 where said gellable composition forms a solid gel sufficient to withstand temperatures of from about 200° to about 310°F.

3. The method as recited in claim 1 where a spacer volume of water is used to cause said gellable composition to penetrate the bottom water zone for at least about one third the distance from said injector well.

4. The method as recited in claim 1 where said formation comprises tar sand.

5. The method as recited in claim 1 where the gellable composition contains an initiator and a retarder in an amount sufficient to allow said composition to travel a desired distance into the bottom water zone.

6. The method as recited in claim 1 where the formation contains a non-aquifer bottom water zone.